The invention relates to an apparatus for supplying medication to the human or animal body, comprising a reservoir for the medication and a conveyance and dosing unit for transporting the medication from the reservoir to a discharge port. The apparatus can be implanted in the body or worn externally on the body.
Apparatus for supplying medication which can be worn on the body of a patient and, in particular, which is suitable for implantation in the body of the patient, should be as small and lightweight as possible. A major demand is also that the medication filled into the reservoir have a sufficiently long stability period in order to achieve refill intervals for the medication which are as long as possible. Apparatus of the type initially cited is known wherein a supply of the liquid medication is stored in high concentration and smallest volumes of the liquid medication are continuously transported, dosed by the reservoir, by a conveyance and dosing unit to the opening of a discharge catheter. However, such apparatus is only suitable for medications which are sufficiently soluble in a liquid which can be tolerated by the body and which are also sufficiently stable over a long period in contact with the apparatus materials at body temperature. In the case of many medications, such as, in particular, insulin, heparin and other polypeptides, however, only relatively low degrees of solubility are manifest and/or stability problems occur at high concentrations. In apparatus for medications of this type, the refill interval for the liquid medication is hence relatively short and there is an overall restriction in the applied use of the apparatus on the patient. Furthermore, in the case of apparatus having a larger supply of liquid medication in the reservoir, there is always the danger that, in case of error, the entire fluid medication will leak out of the reservoir into the patient's body. An overdose of medication such as this, particularly in the case of the administering of insulin during diabetes therapy, can result in severe harm to the patient.